Distant hybridization leads to different ploidy fishes

Abstract

Distant hybridization makes it possible to transfer the genome of one species to another, which results in changes in phenotypes and genotypes of the progenies. This study shows that distant hybridization or the combination of this method with gynogenesis or androgenesis lead to different ploidy fishes with genetic variation, including fertile tetraploid hybrids, sterile triploid hybrids, fertile diploid hybrids, fertile diploid gynogenetic fish, and their derived progenies. The formations of the different ploidy fishes depend on the genetic relationship between the parents. In this study, several types of distant hybridization, including red crucian carp (Carassius auratus red var.) (2n=100, abbreviated as RCC) (female) x common carp (Cyprinus carpio L.) (2n=100, abbreviated as CC) (male), and RCC (2n=100) (female) x blunt snout bream (Megalobrama amblycephala) (2n=48, abbreviated as BSB) (male) are described. In the distant hybridization of RCC (female) x CC (male), bisexual fertile F(3)-F(18) allotetraploid hybrids (4n=200, abbreviated as 4nAT) were formed. The diploid hybrid eggs and diploid sperm generated by the females and males of 4nAT developed into diploid gynogenetic hybrids and diploid androgenetic hybrids, respectively, by gynogenesis and androgenesis, without treatment for doubling the chromosome. Improved tetraploid hybrids and improved diploid fishes with genetic variation were derived from the gynogenetic hybrid line. The improved diploid fishes included the high-body RCC and high-body goldfish. The formation of the tetraploid hybrids was related to the occurrence of unreduced gametes generated from the diploid hybrids, which involved in premeiotic endoreduplication, endomitosis, or fusion of germ cells. The sterile triploid hybrids (3n=150) were produced on a large scale by crossing the males of tetraploid hybrids with females of diploid fish (2n=100). In another distant hybridization of RCC (female) x BSB (male), different ploidy fishes were obtained, including diploid bisexual fertile natural gynogenetic fish (2n=100), sterile triploid hybrids (3n=124), and bisexual fertile tetraploid hybrids (4n=148). Furthermore, two kinds of pentaploid hybrids (5n=172 and 5n=198) were formed. The biological characteristics and the mechanisms of formation of the different ploidy fish were compared and discussed at the cellular and molecular level. The results indicated distant hybridization or the combination of this method with gynogenesis or androgenesis affects the formation of different ploidy fish with genetic variation.

Genomic variation in the hybrids of white crucian carp and red crucian carp: evidence from ribosomal DNA

“…It integrates the genetic material of both parent species into one single group, resulting in changes in the gene regulation and expression in the hybrids [18,20,21]. Thus, the hybrids gain heterosis in many aspects, such as growth rate, desirable traits, harvestability, and environmental tolerances [1,22].…”

Molecular basis and genetic improvement of economically important traits in aquaculture animals

“…Additionally, primordial germ cells (PGCs) and spermatogonial stem cells could be transplanted between two different salmonid species, and resulted in production of donor-derived offspring [45][46][47]. In combination with natural and artificial polyploid fishes with special reproduction modes [18,48], the surrogate approach might have significant values for producing polyploidy stocks in aquaculture or for restoring an endangered species in wild life conservation.…”

Research advances in animal distant hybridization

“…(♀)×Cyprinus carpio xiangjiangnensis (♂) (RC) [1,41,42], Carassius auratus gibelio (♀)×Cyprinus carpio var. xingguonensis (♂) [43], Hypophthalmichthys molitrix (♀)×Aristichthys nobilis (♂) and its inverse cross [17,44,45], Parabramis pekinensis (♀)×Megalobrama terminalis (♂) [46,47], Megalobrama amblycephala (♀ )×Parabramis pekinensis (♂) [48,49], Mylopharyngodon piceus (♀)×Ctenopharyngodon idellus (♂) [50,51], Rhabdosargus sarba (♀)×Pagrosomus major (♂) [52,53], Sparus latus (♀)×Rhabdosargus sarba (♂) [53], Rhabdosargus sarba (♀)×Sparus macrocephalus (♂) [53], Plagiognathops microlepis (♀)×Xenocypris davidi (♂) [54], and Cirrhinus molitorella (♀ )×Sinilabeo decorus tungting (♂) [55,56].…”

“…(♀)×Cyprinus carpio xiangjiangnensis (♂) [41], Cyprinus carpio (♀)×Carassius auratus red var. (♂) (CR) (data not published), Megalobrama amblycephala (♀)× Erythroculter ilishaeformis (♂) (BT) [1], and Erythroculter ilishaeformis (♀) …”